Polymers prepared from conjugated dienes such as 1,3-butadiene are highly unsaturated containing both backbone and pendent unsaturation. The backbone unsaturation of polybutadiene is in the 1,4-trans- or 1,4-cis-configuration and the pendent unsaturation is in the 1,2-butadiene units, hereinafter referred to as either 1,2-microstructure or vinyl configuration. It is frequently desirable to reduce by hydrogenation the unsaturation in polybutadiene or other conjugated diene containing polymers to increase the stability of the polymer or to alter the chemical and physical characteristics of the polymer. Previous processes for hydrogenating polybutadienes or other diene containing polymers preferentially hydrogenated pendent unsaturated groups prior to hydrogenation of backbone unsaturation. It was thus impossible to produce partially hydrogenated polybutadiene having pendent unsaturation and a saturated backbone according to the processes of the prior art as disclosed in U.S. Pat. No. 4,207,409 to Ladenberger et al.
It is highly desirable to produce polymers from conjugated dienes such as polybutadiene having a substantially saturated backbone while creating non-backbone unsaturation for subsequent cross-linking. Such a polymer would be readily curable but would not be easily degraded along the backbone by oxygen or ozone, thus enabling the cured polymer to retain its cured properties.